U.S. patent number 3,602,891 [Application Number 04/805,548] was granted by the patent office on 1971-08-31 for continuous transmission computer and multiple receiver system.
This patent grant is currently assigned to Washington University. Invention is credited to Wesley A. Clark, Charles E. Molnar.
United States Patent |
3,602,891 |
Clark , et al. |
August 31, 1971 |
CONTINUOUS TRANSMISSION COMPUTER AND MULTIPLE RECEIVER SYSTEM
Abstract
Continuous broadcast of computer programs and instructions for
selector utilization by remote data processors. An information
transmission and multiple receiver system wherein the transmitter
continuously repeats transmissions of data primarily consisting of
instructions such as programs, routines and subroutines from its
relatively large central memory. Each receiver can be directed to
any selected portion of the continuous stream of transmitted data
for storage of the selected data in a relatively small memory for
ultimate use by any suitable processor. Transmitted data is
automatically coded in plural bit words and groups of words are
automatically coded in word blocks. The receiver automatically
detects receipt of a selected word block and automatically
processes the words within the selected word block into its memory
in a directed program. As a result of this system and process,
individual, low-power data processors at each receiver are
empowered with a much greater processing capability from the
program data broadcast from the transmitter's large central memory
and selectively stored in the receiver's smaller memory.
Inventors: |
Clark; Wesley A. (St. Louis,
MO), Molnar; Charles E. (St. Louis, MO) |
Assignee: |
Washington University (St.
Louis, MO)
|
Family
ID: |
25191883 |
Appl.
No.: |
04/805,548 |
Filed: |
March 10, 1969 |
Current U.S.
Class: |
709/219;
709/213 |
Current CPC
Class: |
H04L
12/1836 (20130101) |
Current International
Class: |
H04L
12/18 (20060101); H04n 007/08 () |
Field of
Search: |
;178/69.5,4.1
;325/55,58,54 ;340/172.5 ;235/151 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Zache; Raulfe B.
Claims
We claim:
1. A transmission and receiver system comprising at least one
transmitter and a plurality of receivers, the transmitter including
a memory storage device for storing groups of data signals
comprising computer programs, means to address the memory storage
device to identify portions of the stored data signals that are to
be read out of the memory storage device according to a
predetermined schedule, means to read out groups of the data
signals thus identified continuously from the memory storage
device, means to transmit the groups of data signals read out from
the memory storage device to a transmitting station for
transmission thereby as a continuous broadcast, each receiver
comprising means to receive the continuous broadcast including the
data signals transmitted thereby, means to generate synchronizing
signals in the transmitter, means to synchronize the data signals
transmitted by the transmitter with the synchronizing signals,
means to generate synchronizing signals in the receiver
synchronized to the transmitter synchronizing signals, and means to
synchronize the data signals received by the receiver with the
synchronizing signals generated by the receiver, a processor having
a memory section, each receiver having means to identify selected
ones of the plurality of data groups for transfer to its memory
section, and means to transfer the thus identified plurality of
data groups to the memory section of the processor thereby making
the data signals comprising computer programs available for use by
each processor to increase the information processing capability of
each processor.
2. The system of claim 1 wherein the transmitter has means
controlled by the address means for generating coding signals to
identify specific pluralities of the said groups of data signals,
means to add the identifying signals at predetermined times to the
groups of data signals prior to transmission thereof to enable
identification of selected ones of the plurality of groups of data
signals, the receiver having a comparator, means to provide the
comparator with other signals identifying a specific plurality of
groups of data signals that is to be selected for storage in the
memory section, the comparator having means to compare the
identifying signals with the data signals received by the receiver,
and means controlled by the comparator and responsive to a match of
signals sensed by the comparator for enabling the receiver to
transfer groups of data signals to its memory section.
3. The system of claim 1 wherein the synchronizing signals
generated by the transmitter comprise color television black burst
signals and the receiver includes a television receiver front end
unit for receiving the transmitted signals and for generating the
synchronizing signals.
4. The system of claim 3 wherein the transmitter includes means to
generate a standard color television carrier signal, means
including a color television modulator for modulating the carrier
signal with the groups of data signals and the black burst signals,
and the receiver includes a color television signal demodulator for
demodulating the modulated carrier signal to produce the groups of
data signals and the black burst signal.
5. A method for using a system of one or more transmitters and a
plurality of receivers for the continuous broadcast of computer
programs to the receivers for selective utilization at the
receivers to process information comprising the steps of storing
the computer programs in the form of information bits in a central
memory at the transmitter reading out the information bits from the
central memory in a predetermined order, continuously transmitting
the information bits in a broadcast stream, at each receiver
identifying a selected portion of the broadcast stream, and writing
the selected portion of the broadcast stream into a local memory
storage unit at the said receiver and using the information thus
stored for the purpose of programmed operation of an information
processing part of each receiver.
6. The method of claim 5 including the steps of coding portions of
the serial broadcast stream to identify the content thereof, the
said steps of identifying a selected portion of the serial
broadcast stream including the step of comparing the received
signals with predetermined signals.
7. The method of claim 6 including synchronizing the information
bits with a standard color television black burst signal.
8. The method of claim 6 including the steps of collecting
predetermined numbers of the information bits as words, and
grouping predetermined numbers of the words in groups, each said
code identifying a word group.
9. The method of claim 5 including the steps of converting the
information bits to analog signals prior to transmission thereof,
and converting the analog signals to digital signals following
receipt thereof by the receivers.
10. A method a communicating logical information comprising
computer programs from a central storage source to a plurality of
receivers for processing information at the receivers utilizing
selected portions of the logical information to increase the
information processing information at the receivers comprising the
steps of continuously repeating the cycle of extracting information
bits comprising computer programs in a predetermined sequence from
a memory storage device containing the computer programs, coding as
words predetermined groups of the computer program information
bits, generating synchronizer signals, synchronizing the computer
program information bits with the synchronizer signals,
transmitting in a continuous broadcast the synchronized computer
program information bits as a continuously repeating cycle of
signals to a plurality of independent receivers, selecting
independently at each receiver portions of the transmitted computer
program information bits, and at each receiver writing the portions
of computer program information bits selected by that receiver into
a memory unit for use of the selected computer programs to process
information at the receiver.
11. The method of claim 10 including the step of coding
predetermined portions of the computer program data bits according
to subject matter prior to transmission thereof, and selecting the
said portion after receipt thereof by a receiver by designating the
particular coding therefor.
12. A method of using broadcast apparatus to increase the
information processing capability of a plurality of individual
receivers comprising the steps of continuously broadcasting a
repeating cycle of computer programs derived from a relatively
large information storage device, at each receiver selectively
identifying portions of the broadcast programs according to which
programs are to be used at each receiver, directing the selected
portions of computer programs thus identified to a memory section
of each receiver, and independently utilizing the computer programs
stored in the memory section of each receiver to process
information by a processor at that receiver.
13. The method of claim 12 including the steps of addressing the
memory storage device of shift information bits comprising words of
computer programs in parallel from the memory storage device,
converting the words to a serial stream of the information bits,
converting the serial stream of information bits to an analog
signal, broadcasting the analog signal for receipt by all the
receivers, at each receiver reconverting the analog signal to a
serial stream of information bits, at each receiver identifying
from the serial stream of information bits selected groups of the
information bits that are to be retained at that receiver by being
directed to the memory section thereof.
Description
BRIEF DESCRIPTION OF THE INVENTION
This invention provides a computing or data processing system
having a relatively large but simple central storage and
transmission system which transmits fixed programs or data to a
large number of receivers. The transmitter can continuously
broadcast all of the information in its library over one or a
plurality of transmission bands. Information, utilizing the
transmitted computer programs processing is carried out by the
receivers, which selectively extract information from the
continuous broadcast stream as needed. Any number of independent
receivers can select different portions of the broadcast stream or
can simultaneously make use of the same parts (or all) of the
broadcast information. The continuously available broadcast
information comprising computer programs to be selected by the
receivers thus permits large numbers of very small receivers with
limited local working storage to do very large and complex jobs at
low cost.
Many different applications can be effectively dealt with by means
of the system of this invention. A system of desk calculators for
example, would require almost no local storage and yet would be
able to execute a large and easily augmented set of complex
arithmetic functions and table look-up procedures. Another use
would be to provide a large and rapidly accessed library of
programs and data to a number of small locally programmable
computers. Hospital intensive care monitoring could be accomplished
by a large number of independent but identical receivers acting as
bedside stations, each selecting from the broadcast library those
programs needed to carry out its assigned monitoring tasks. Each of
these stations could, in turn, be a part of a data gathering or
supervisory network unrelated to the broad casting system. The
broadcasting system would serve to logically impower the individual
receivers.
Two important design parameters of the broadcasting system are the
total size of the library (the totality of information available to
a given receiver) and the time needed to gain access to information
within it. The desirable system minimizes the local working storage
and complexity of the receivers for a given system through the
proper choice of number of transmitters, storage medium, number and
characteristics of transmission channels, message coding, and
broadcast schedules. A broadcasting system according to the
invention would, for example, be capable of transmitting 1 million
bits 30 times per second over coaxial cables. Such a broadcasting
system, with simple receivers having local working storage of the
order of 10.sup.2 to 10.sup.4 bits (perhaps augmented with modest
local backup storage) for example, would be adequate to handle
several applications. This invention may extend to relatively
complicated systems containing a multiplicity of transmitters
serving overlapping populations of receivers, but the example
described herein relates in general to a simple system with a
single transmitter serving a single family of receivers.
The transmitter must store and repeatedly transmit a fixed library
of information reliably and economically. In its simplest form, the
transmitter spews out a single stream of serial binary information,
repeating the stream cyclically and continuously. For some
purposes, it may be desirable to have a more rapid access to some
parts of the transmitted library than to others. This may be
accomplished by repeating certain information several times in one
transmission of the complete library, or by transmitting several
different parts of the library simultaneously, each with a
different cycle time, over more than one parallel transmission
channel.
The principle component of the transmitter is the storage device
used to hold the library. Depending upon the application, the
storage device or memory may be embedded in a more or less complex
system for loading the library, making modifications to its
contents, and controlling the readout of the stored information. At
least three or four different types of storage units may be used,
including the delay line, the rotating memory (disc, or drum),
various photographic techniques, and the random access magnetic
core or film memory.
Typical acoustic delay lines can store and deliver several thousand
bits at rates of 1 to 20 million bits per second. A 5,000 bit line
which operates at 1 megabit per second is a representative example
of an acoustic delay line that is commercially available. The
difficulties of loading information into a delay line, the relative
small storage capacity, and the fixed delay time make the acoustic
delay line appear to be attractive primarily for small and highly
specialized systems in which the low cost can be exploited.
For large libraries, rotating memories such as discs, drums or
photographic memories may be used. A typical disc of moderate size
is capable of storing 100,000 bits on each of 64 tracks and can
deliver information at a rate of 3 million bits per second per
track. Depending upon the number of heads employed for reading, the
disc can deliver information at rates from 3 million to 192 million
bits per second. The rotation rate is typically 1/30 or 1/60 of a
second, but smaller access times can be obtained by placing heads
at several positions along the circumference of a track, The
relatively low cost (a fraction of a cent per bit for 5.times.
bits) and the cyclic delivery of information at a constant bit rate
make the disc a useful storage unit if the size of the library is
sufficiently large and the fixed time per rotation is
tolerable.
Random access magnetic memories have advantages in flexibility of
timing and allow easy loading and modification of the stored
library. Bit rates from zero up to 30 million or more per second
can be obtained with a single memory array, and paralleling of more
than one memory array for even higher rates is easily done. Complex
broadcasting schedules in which certain segments of the library are
repeated more than once in a complete broadcasting schedule can be
accomplished easily without requiring storing of the repeated
sections at more than one place in the memory. For small to
moderate libraries, ranging up to 10.sup.5 or 10.sup.6 bits, a
transmitter using random access magnetic storage may be used.
Photographic memories may be appropriate for stable libraries of
very large size.
The transmission system must accept the output of the transmitter
and distribute it to each receiver. The principal system design
parameters are the number of transmission channels, the information
transmission rate of each channel, and the treatment of
transmission errors. Media for transmission channels range from
telephone lines, capable of transmission rates of a few thousand
bits per second, through coaxial cables of intermediate capacity,
and up to microwave links capable of transmitting many millions of
bits per second. It is possible to use this invention as a kind of
"information distributing utility" with an enormous library on many
channels, selectively available to different classes of receiver
"subscribers" over a comprehensive transmission system employing
various types of channels for different parts of the service.
In addition to the choice of transmission medium, a choice must be
made of the form of encoding that is to be used. The simplest case
may employ a single coaxial cable carrying a self-clocking
pulse-width-modulated signal transmitted directly without any
carrier. For more complex systems, particularly those using
electromagnetic radiation as the medium or those multiplexing
several channels on a single cable, more complex modulation schemes
would be appropriate.
The receiver may conveniently be thought of as made up of two major
functional parts. The receiver front end consists of the necessary
apparatus to select broadcast channels, demodulate and decode the
information carried thereon, detect the arrival of a desired
portion of the library, and deliver it to the processor. It may be
convenient to consider any information buffering used in the
reception of the message as part either of the front end or of the
processor, depending upon what other use is made of the buffer by
the processor. A typical front end will accept the code designation
of a desired portion of the library and carry out the channel
switching and all other operations needed to obtain the requested
information. The processor part of the receiver may be any
conventional processor specialized to the application. As such the
processor has the usual input-output capability to receive data,
process the data with the instructional programs received from the
transmitter, with or without any additional programming of the
processor, and produce the results at its output.
In the illustrated embodiment of this invention, a reasonably
general and flexible broadcasting system is set forth. For the
transmitter, particularly illustrative in this specification, a
core memory of 32,768, 12-bit words with a cycle time of about 2
microseconds is described. This provides a flexible, accessible and
efficient transmitter capable of delivering about 1.5 megabits per
second on a single channel. For a transmission system, a modified
community antenna television system (CATV) would transmit video (4
mHz.) bandwidths on up to 12 channels, lying in the VHF television
bands, via a coaxial cable distribution network. The color
television receiver front-end includes a tuner, i-f strip and
second detector, providing a 4-mHz. signal for further
demodulation. Such a system can be used to provide, for example, a
desk calculator with little or no local storage, a patient
monitoring subsystem for operations such as waveform analysis of
EKG records, and program and data library support for small
computers.
Thus, this invention provides and effectively simultaneous one-way
transmission of information to many small and potentially very
simple computers or other kinds of processors. The dispatching and
priority problems usually associated with the sharing of a central
storage element by a large number of peripheral terminals are
eliminated, and the number of receivers can be indefinitely
increased in a given system without any alteration to the
transmitter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic block diagram of the central storage and
transmission system.
FIG. 2 is a schematic block diagram of the receiver.
DETAILED DESCRIPTION OF THE INVENTION
The central storage and transmission system 20 has a conventional
digital memory storage device 21 which, for example, may store
32,768 words, each containing 12 bits. The memory storage device 21
is addressed by an address register counter 22 that, in the present
example, provides for sequential scanning through the entire memory
cycle and, as will be described, causes the scanning to be
continually repeated. Selective or random scanning could be
programmed if desired by devices known to the art.
An address input conductor bank 23 leads from the address register
counter 22 to the memory storage device 21 to deliver address
signals to the storage device 21. There is also a conductor 26
leading from the memory storage device 21 to the address register
counter 22 that carries an indexing signal at the end of each cycle
of locating a word by the memory storage device 21. The address
register counter 22 is of a kind that, when triggered by the
indexing signals supplied through the conductor 26, causes the
address next in numerical sequence to be delivered to the memory
storage device 21. Another input conductor 27 to the memory storage
device 21 delivers a signal, derived as will be described, to
instruct the memory storage device to locate the word to which the
memory storage device has been directed by the address register
counter 22.
The memory storage device 21 has 12 output conductors 28 for
transferring the 12 bits of a word in parallel to a buffer register
29. The buffer register 29 has 12 output conductors 30 for
transferring the 12 bits of a word from the buffer register 29 to a
shift register 31. A conductor 32 delivers a signal from the memory
storage device 21 to the buffer register 29 to initiate transfer of
the word from the memory storage device 21 to the buffer register
29, when the memory storage device 21 has located the word to which
it was addressed. A conductor 33 supplies a signal, derived as will
be described, to the shift register 31 to initiate transfer of a
word from the buffer register 29 to the shift register 31. An
output conductor 34 leads from the shift register 31. Another
conductor 35 supplies selected high-frequency clock pulses to the
shift register 31 to cause serial shifting of the bits of a word as
serial digital data from the shift register 31 to its output
conductor 34.
In addition, a conductor 36 delivers a 1 signal to the buffer
register on certain counts of the address register counter 22, to
be described. A conductor 37 transmits this special 1 signal to the
shift register 23.
It has been said that the shift register 31 is triggered by clock
pulses, and it will become apparent that these clock pulses are
delivered to other parts of the system. To produce these clock
pulses, there is a crystal oscillator 40 that generates a
sinusoidal signal at a frequency of 3.57954 mHz. in its output
conductor 41. The output from the crystal oscillator 40 is supplied
by an input conductor 42 to a black burst generator 43 and also, by
an input conductor 44, to a device 45 digitizing and halving the
frequency of its sinusoidal wave input to produce a square wave
output signal phase locked to the oscillator frequency. This square
wave output signal is referred to herein as a clock pulse
signal.
The clock pulse signal is transmitted by a conductor 46 to the
input conductors 47, 48, 49 and 50 of a plurality of AND gates 51,
52, 53 and 54, respectively, and also by a conductor 55 to a delay
device 56. The delay device 56 delivers the delayed clock pulse
through a conductor 57 to a counter 58 that is designed to count
the input clock pulses beginning with a count of 0 through and
ending with a count of 113 with the 114th pulse causing a return to
a count of 0, thereby continuously repeating the count cycle of 0
through 113 for establishing the basic cycle of the system. The
counter 58 has an output conductor 59 that transmits a signal to
the AND gate 51 on a 94 count in the counter 58. Another conductor
60 transmits a signal to the AND gate 52 upon a count of 0 in the
counter 58. A conductor 61 transmits a signal to the AND gate 53 on
a count of 97 in the counter 58. Another conductor 62 transmits a
signal to the AND gate 54 on a count of 105 in the counter 58.
The AND gate 51 has an output conductor 63 leading to the "set"
input of a blanking flip-flop 64. The AND gate 52 has an output
conductor 65 leading to the "reset" or "clear" input of the
blanking flip-flop 64. The AND gate 53 has an output conductor 66
leading to the "set" input of a horizontal sync flip-flop 67. The
AND gate 54 has an output conductor 68 leading to the "reset" or
"clear" input to the horizontal sync flip-flop 69.
A conductor 72 delivers a signal from the "set" output of the
blanking flip-flop 64 when the blanking flip-flop is in its "set"
condition. A conductor 73 delivers a signal from the "set" output
of the horizontal sync flip-flop to the black burst generator 43
when the horizontal sync flip-flop is in its "set" condition. With
these blanking and horizontal sync signals and with the sinusoidal
wave supplied from the input conductor 42, the black burst
generator 43 can and does generate a typical black burst signal,
like a color television signal without picture or color
information, which it delivers to an output conductor 74 for a
purpose to be described. The black burst signal has the duration of
the blanking pulse to which the horizontal sync signal and then the
high-frequency sinusoidal wave signal are added.
A startup synchronizer 78 has an input conductor 79 leading from a
"start" or "run" pushbutton 80. Another input conductor 81 to the
startup synchronizer leads from a "preset" pushbutton 82 which
produces an initial clearing signal. Another input to the startup
synchronizer 78 comes from a conductor 83 connected to the "reset"
or "clear" output of the blanking flip-flop 64. The startup
synchronizer 78 has a conventional arrangement of flip-flops and
gates to synchronize the "run" signal with the horizontal blanking
signal to assure that the output from the startup synchronizer does
not occur during blanking. The output from the startup synchronizer
is delivered by a conductor 85 to an "AND" gate 86. Another input
conductor 87 to the AND gate 86 leads from the "reset" or "clear"
output of the blanking flip-flop 64 to deliver a "nonblanking"
signal to the and gate 86 when the blanking flip-flop is in its
"reset" condition.
The clock pulse signal from the digitize and halve frequency device
45 is delivered by an input conductor 88 to the AND gate 86. One
other input conductor 89 to the AND gate 86 delivers a signal to be
described that normally permits the AND gate 86 to pass the clock
pulse signal delivered by the conductor 88.
A conductor 92 connects the output from the AND gate 86 to deliver
clock pulses to a delay device 93, the clock pulse output of which
is transmitted by a conductor 94 to a transfer and shift counter
95. The transfer and shift counter 95 counts the clock pulses
supplied to it in repeated cycles of 0 through 13 with the 14th
pulse causing a return to count 0. It has an output conductor 96
for delivering a signal signifying that the counter is registering
a 0 count to an inverting device 97 which in turn transmits a
signal only when the transfer and shift counter 95 is not
registering a 0 count. A conductor 98 leads from the inverting
device 97 to an AND gate 99. Another input to the AND gate 99 is
supplied by a conductor 100 that carries clock pulses from the AND
gate 86. The output from the AND gate 99 is connected to the input
conductor 35 leading to the shift register 31.
The 0 count signals from the transfer and shift counter 95 are
supplied by another conductor 201 to an AND gate 102. Another input
conductor 103 to the AND gate 102 leads from the conductor 92
carrying the clock pulses from the AND gate 86. The output from the
AND gate 102 is connected to the input conductor 33 to the shift
register 31.
Another conductor 105 from the transfer and shift counter 95
delivers a pulse to a word counter 106 only when the transfer and
shift counter 95 makes the transition from count 13 to count 0 or,
in other words, on the 14th pulse, during each 0-13 count cycle.
The word counter 106 is designed to continuously repeat the cycle
of counting words from 0 to 6, with the seventh pulse causing a
return to count 0. The word counter 106 has an output conductor 107
that, upon counting each fifth word, delivers a signal to an
inverting device 108. Hence, the inverting device 108 supplies a
signal on all word counts except for the duration lasting from the
end of the fifth word count to the end of the sixth word count, and
for the latter duration the inverting device 108 supplies no
signal. The output from the inverting device 108 is transmitted by
a conductor 109 to an AND gate 110. Another input conductor 111 to
the AND gate 110 is connected to the output from the AND gate
102.
The output from the AND gate 110 is transmitted by a conductor 112
to an OR gate 113. The output from the OR gate 113 is connected to
the conductor 27 leading to the memory storage device 21. Another
input conductor to the OR gate 113 delivers horizontal sync pulses
from an AND gate 115. These horizontal sync pulses from the AND
gate 115 are also transmitted by a conductor 116 to the word
counter 106 to reset the word counter 106 to 0. One input to the
AND gate 115 constitutes the horizontal sync pulse supplied by a
conductor 117 connected to the "set" output of the horizontal sync
flip-flop 67. The other input to the AND gate 115 is delivered by a
conductor 118 connected to the output from the startup synchronizer
78.
A conductor 120 leading from the word counter 106 delivers a signal
to an inverting device 121 only following a sixth word count by the
word counter 106 and until the transmission of a horizontal sync
pulse to the word counter during each word count cycle. Hence, the
inverting device transmits a signal at all times except for the
duration lasting from the end of a sixth count to the beginning of
the following horizontal sync pulse. The output from the inverting
device 121 is transmitted by the conductor 89 to the AND gate
86.
The "preset" signal, generated upon depression of the "preset"
pushbutton is delivered by a conductor 123 to the transfer and
shift counter 95. This "preset" signal is also delivered to the
word counter 106 by a conductor 124 and to the address register
counter 22 by a conductor 125.
The output conductor 34 from the shift register 31 transmits the
serial digital signal from the shift register to a digital to
analog converter 128. A conductor 129 transmits the analog signal
from the digital to analog converter 128 to a summing amplifier
130. The other input to the summing amplifier is the black burst
signal delivered by the conductor 74 from the black burst generator
43. The summing amplifier 130 produces a video signal pg,12
containing the black burst signal and the analog signal
corresponding to the word shifted out of the shift register 31.
This video signal is transmitted by a conductor 131 to an RF
modulator 132, and the modulated signal is transmitted by a
conductor 133 to a summing circuit and amplifier network 134 to
which other signals generated by systems corresponding to this
central storage transmission system 20 are also delivered, as by
conductors 135, 136, 137 and 138. An output connection 139 enables
connection of the summing circuit and amplifier network 134 to a
television transmission cable array (not shown).
FIG. 2 is a schematic diagram of a receiver 150. The receiver 150
has a conventional color television receiver "front end" 151 that
has an input connection 152 to which the cable network carrying the
signals transmitted by the central storage and transmission system
20 is connected. As will be described, the receiver 150 operates
upon this signal received by the color TV receiver 151 to
ultimately supply information to a processor 153 that may comprise
any conventional processor desired for processing input data with
computer programs supplied by this broadcast system and, as desired
also input directly to the processor 153. The additional processor
153 contains an internal memory section 154 that may be much
smaller than the memory section 21.
The additional processor is joined to its memory section 154 by a
suitable plurality of conductors 155, 156, 157, 158, 159, and 160.
These conductors 155-160 provide memory access pathways used in
conventional operation of the processor 153. An address register
counter 161 has an output conductor bank 162 that transmits address
signal to the memory section 154. In this example of the invention,
the address register counter 161 directs the memory section 154
sequentially through its storage of 12-bit words. Another conductor
163 is connected from the memory section 154 to the address
register counter 161 to deliver an end-of-cycle pulse at such time
as the memory section 154 has received and stored a 12-bit word at
the proper position in its memory as dictated by the address signal
in the conductor bank 162. There are suitable conductors 164, 165
and 166 illustrative of the means by which the processor 153
communicates with the address register counter 161 in the
utilization of information contained in the memory section 154. The
address register counter 161 has a suitable conventional means (not
shown) for disabling the transmission of end-of-cycle pulses
through the conductor 163 when signals are being transmitted
through the conductors 155-160 or through the conductors
164-166.
The color TV receiver "front end" 151 has a conventional receiver
means 167 for selecting any one of the several channels to select
any one of several information streams being transmitted by a
plurality of central storage transmission systems like the system
20 previously described. The color TV receiver 151 separates the
received signal into video, phase-locked color subcarrier, blanking
and horizontal sync component signals. The video signal is supplied
to an output conductor 168. The phase-locked color subcarrier
signal is supplied to an output conductor 169. The blanking signal
is supplied to an output conductor 170. The horizontal sync signal
is supplied to an output conductor 171. The video signal is also
transmitted as an analog signal directly to the additional
processor elements 153 by a conductor 172.
The video signal from the color TV receiver front end 151 is
transmitted through the conductor 168 to an analog to digital
converter 175. An output conductor 176 from the analog to digital
converter 175 carries the digital bit data corresponding to the
word bits shifted out of the shift register 31 of the central
storage transmission system 20. This digital bit data is
continually transmitted in series through the conductor 176 to an
assembly shift register 177 into which the data is shifted and held
as parallel information upon receipt of certain shift pulses by the
assembly shift register 177 as will be described.
The phase locked color subcarrier signal is delivered by the
conductor 169 to a signal standardizer 179 that digitizes its input
to a square wave. The square wave output from the signal
standardizer 179 is transmitted by a conductor 180 to a
frequency-halving device 181 that halves the frequency of its
input. The input from the frequency-halving device 181 constitutes
a clock pulse signal identical to the clock pulse signal produced
in the central storage transmission system 20 and phase-locked to
the blanking signal as will be described. This clock pulse signal
is transmitted from the frequency-halving device 181 through a
conductor 182 to an AND gate 183 and though a conductor 184 to an
and gate 185.
The blanking signal from the color TV receiver front end 151 is
transmitted through the conductor 170 to a signal standardizer 188.
The output from the signal standardizer 188 is transmitted by a
conductor 189 to an inverting device 190 that delivers no signal
when there is a signal in the input conductor 189 and that does
deliver a signal when there is no signal in the input conductor
189. The output from the inverting device 190 is delivered by a
conductor 191 to the frequency-halving device 181 to phase-lock the
clock pulse signal with the blanking signal. The output from the
inverting device 190 is also transmitted by another conductor 192
as an input to the AND gate 185.
The horizontal sync pulse from the color television receiver front
end 151 is transmitted through the conductor 171 to a signal
standardizer 195. The output from the signal standardizer 195 is
transmitted by a conductor 196 to a word counter 197 to set the
word counter to a word count of 0. The word counter 197 is designed
to continuously repeat the cycle of counting words from 0 through
6. Another conductor 198 transmits the output from the signal
standardizer 195 to a shift and transfer counter 199 to set the
shift and transfer counter to 0. The shift and transfer counter is
designed to continuously repeat the cycle of counting pulses from 0
through 13.
The word counter 197 has an output conductor 200 that is connected
to transmit a signal from the word counter 197 onlY upon a count of
6. This conductor 200 leads to an inverting device 210 that
delivers a signal when there is no signal in the input conductor
200 (when the word counter is not registering a count of 6), and to
deliver no signal when there is a signal in the input conductor 200
(when the word counter is registering a count of 6). The output
from the inverting device 210 is delivered by a conductor 202 to
the AND gate 158.
The output from the AND gate 185 is transmitted by a conductor 205
to a delay device 206 the output from which is delivered by a
conductor 207 to the shift and transfer counter 199. An output
conductor 209 leads from the shift and transfer counter 199 to
carry a signal when the shift and transfer counter registers a
count of 13. The conductor 209 leads to an inverting device 210 the
output from which is connected by a conductor 211 to the AND gate
183. The inverting device delivers a signal to the AND gate 183 on
all counts from 0 to 12 but delivers no signal when the shift and
transfer counter is registering a count of 13. The AND gate has an
output conductor 212 for delivering clock pulses to the assembly
shift register 177.
Another signal from the shift and transfer counter 199 is
established following a count of 13 until the end of the next
succeeding 0 count. This signal is transmitted by a conductor 214
as an indexing signal to the word counter 197. This same signal,
constituting a word-assembled pulse, is also transmitted by a
conductor 215 to a start/stop synchronizer 216. Finally, this same
signal from the shift and transfer counter 199 is transmitted by
another conductor 217 to a delay device 218, the output from which
is transmitted by a conductor 219 to an AND gate 220. Another
conductor 221 connected to the input of the AND gate 220 leads from
the start/stop synchronizer 216 and delivers a signal to the AND
gate 220 when the start/stop synchronizer 216 is in the "set" or
"on" condition, which occurs in a manner to be described. The
output from the AND gate 220 is delivered by a conductor 223 to one
AND gate 224 and by another conductor 225 to another AND gate
226.
Another input to the AND gate 224 constitutes a "match" signal
delivered by a conductor 228 leading from a comparator 229. The
comparator 229 is programmed from the processor 153 through a
plurality of conductors 230 with a "tag number" corresponding to
identifying number of the word block to be selected for
transmission to the memory section 154. There is also a device 231
that continuously transmits a 1 signal through a conductor 232 to
the comparator 229.
There are 12 conductors 234 leading from the assembly shift
register 177 to the comparator 229 to enable comparison of the 12
bits of a word resting in the assembly shift register with the
twelve bits of the "tag number" supplied to the comparator 229
through the conductors 230. There is also a conductor 235 that
transmits a 1 signal from the assembly shift register 177 to the
comparator whenever the word in the assembly shift register is a
block identifying word.
There are 12 conductors 237 for delivering the 12-bits of a word in
the ta block to a buffer register 238. Twelve other conductors 239
deliver the 12-bit word in parallel to the memory section of the
processor 154 when the buffer register 238 is directed to do so as
will be described.
A conductor 242 leading from the processor 153 delivers a start
selection/transfer process signal to the start/stop synchronizer
216 when the processor 153 seeks certain information from the total
stream of information transmitted by the transmission system 20.
This start selection/transfer process signal is also delivered by
another conductor 243 to a block transfer counter 244. The block
transfer counter 244 is designed to continuously repeat cycles of
counting pulses from 0 to 255. When a signal is transmitted through
the conductor 243, that signal sets the block transfer counter 244
to a count of o.
Upon completion of a count of 255 and a subsequent count of 0, the
block transfer counter 244 transmits an output signal through a
conductor 245 to the start/stop synchronizer 216 to stop operation
thereof. This same signal is transmitted by a conductor 246 to the
processor 153 to communicate to the processor the fact that an
entire block of 256 works has been counted by the block transfer
counter 244.
The block transfer counter 244 has an output conductor 248 that
delivers a signal to an inverting device 249 only when the block
transfer counter registers 0. An output conductor 250 from the
inverting device 249 carrier no signal when there is a signal in
the input conductor 248 corresponding to a count of 0 and transmits
a signal during all other counts of 1 through 255 by OR block
transfer counter 244 since, during the 1 through 255 counts, there
is no signal in the conductor 248. The conductor 250 constitutes
another input to the , gate 266.
The output from the AND gate 224 is transmitted by a conductor 252
to an OR gate 253. The output from the AND gate 226 is also
delivered by another conductor 254 to the OR gate 253. The output
from the OR gate 253 is delivered by a conductor 255 to a transfer
input to the buffer register and by a conductor 256 to a transfer
input to the memory section 154. The output from the OR gate 253 is
also delivered by a conductor 257 to a delay device 258. The output
from the delay device 258 delivers indexing pulses through a
conductor 259 to the block transfer counter 244.
OPERATION
It will be understood that this invention contemplates the
connection of a large number of receivers 150 to the cable network
array. With one or more transmission systems 20, depending upon the
volume of information it is desired to store, continuously
transmitting the stored data in repeating cycles, the receivers can
independently select what portion of any transmission cycle is to
be received. Accordingly, since at any one time each receiver will
receive and process only a relatively small portion of the total
library of information stored by the transmitter or transmitters,
each receiver is a relatively simple device with a relatively small
memory capacity. When changes are made in the information stored in
the library, such changes are made only at the transmitter or
transmitters rather than at the large number of local receiver
stations. Furthermore, the computer power of each receiver can be
low because of the selective availability of computer programs that
are being continuously broadcast by the transmission system 20.
Various components of the transmission system 20 are set for
initiating operation by depressing the preset pushbutton 82. The
preset signal supplied by the conductor 123 to the transfer and
shift counter 95 clears that counter to a count of 0. The present
signal supplied by the conductor 124 to the word counter 106 sets
the word counter to a count of 6. The preset signal supplied by the
conductor 125 to the address register counter 22 clears the address
register counter to a count of 0. The preset signal supplied by the
conductor 81 clears the synchronizer 78 in preparation for receipt
of the run signal. The transmission system 20 is started by
depressing the run pushbutton 80.
Clock pulses phase-locked with the sinusoidal signal generated by
the crystal oscillator 40 are transmitted to the AND gate 86. These
clock pulses are passed through the AND gate 86 so long as there is
a nonblanking signal in the conductor 87 from the "reset" output of
the blanking flip-flop 64, a signal in the conductor 85 from the
startup synchronizer 78 signifying the system has been set to run,
and a signal in the conductor 89 indicating the word counter 106 is
not in the counting state between the end of the sixth word and the
beginning of the horizontal sync pulse. The transfer and shift
counter 95 counts the input clock pulses passed by the AND gate 86
to initiate several functions: unloading of a word from the memory
storage device 21 into the buffer register 29, dumping of a word
from the buffer register 29 to the shift register 31, shifting out
of bits from the shift register 31 to its output conductor 34, and
counting of works in the word counter 106.
A horizontal sync signal is supplied by the conductor 114 to the OR
gate 113 and is passed by the OR gate 113 to the unload input
conductor 27 leading to the memory storage device 21. This signal
causes the memory storage device 21 to read the 12-bit word to
which it has been programmed or addressed for unloading to the
buffer register 29. As soon as the 12-bit word has been read by the
memory storage device 21, a data available signal is transmitted
from the memory storage device through the data available conductor
32 to the buffer register 29, causing the 12-bit word to be
transferred (copied) through the conductors 28 into the buffer
register 29 along with a special signal through the conductor 36
from the address register counter 22 as later described. Since the
horizontal sync pulse occurs only once during each scanning line
(established by the period of the counter 58), it causes unloading
of only the first of the six words that are read out in each
scanning line.
As soon as the memory storage device has completed the cycle of
reading and dumping a work into the buffer register 29, it produces
a signal in the end of cycle conductor 26 that is transmitted as an
indexing signal to the address register counter 22. This causes the
address register counter 22 to transmit the next address through
the conductors 23 to prepare the memory storage device 21 to read
the next word it is storing. 13.
A signal representing a 0 count is supplied by the transfer and
shift counter 95 and delivered to the conductors 96 and 101. This 0
count signal is inverted in the inverting device 97 so that the AND
gate 99 passes the clock pulse signal delivered to it through the
conductor 100 only when the transfer and shift counter does not
register 0 or, in other words, during the counts from 1 through 13.
These clock pulses are passed by the AND gate 99 to the shift input
conductor 35 to cause any 13-bit word then held in the shift
register 31 to be transferred in series to the shift register
output conductor 34.
The clock pulse signal passed by the AND gate 86 is supplied to the
conductor 103 leading to the AND gate 102. So long as there is a o
count in the transfer and shift counter 95, the AND gate 102 passes
a clock pulse to the AND gate 110. Unless there is no signal in the
conductor 109, constituting an inhibiting condition that appears
from the end of counting the fifth word to the end of counting the
sixth word in the word counter 106, the AND gate 110 passes the
clock pulse signal to its output conductor 112 and delivers that
clock pulse signal to the OR gate 113. This clock pulse signal is
passed by the OR gate 113 to the unload input conductor 27
directing the memory storage device 21 to unload the word to which
it has been addressed by signals in the conductor bank 23 from the
address register counter 22. Shortly thereafter, the memory storage
device 21 delivers a signal in the data available output conductor
32 that leads to the buffer register 29. This data available signal
triggers the buffer register 29 to cause the 12-bit word to be
unloaded from the memory storage device 21 through the conductors
28 to the buffer register 29 along with a special signal through
the conductor 36 from the address register 22 as later
described.
The transfer and shift counter 95 transmits a signal through the
conductor 105 to the word counter 106. A signal is transmitted to
the output conductor 105 only after the transfer and shift counter
95 has counted a total of 14 clock pulses (the 14th pulse occurring
during the transition from count 13 to count 0).
The first clock pulse passed through the AND gate 86 after the end
of a blanking signal is transmitted to the AND gates 99 and 102.
Since at this time the transfer and shift counter 95 registers 0,
the AND gate 99 is blocked and the AND gate 102 is open to transmit
the clock pulse through the conductor 33 to the shift register 31.
This clock pulse therefore causes the 13-bit word in the buffer
register 29 to be transferred to the shift register 31. This same
clock pulse is delivered through the conductor 111, through the AND
gate 110 and the OR gate 27 to cause a 12-bit word to which the
memory 21 has been addressed to be transferred to the buffer
register 29.
When the second clock pulse passed by the AND gate 86 is
transmitted to the AND gates 99 and 102, the clock pulse is passed
by the AND gate 99 but is blocked from passing through the AND gate
102 because the transfer and shift counter now registers a 1 (not
0). Therefore, no signal is passed by the AND gate 102 to the AND
gate 110. Hence, the AND gate 110 cannot transmit a pulse to the
output conductor 112 and no signal is transmitted through the OR
gate 113 to the unload input conductor 27. Accordingly, the memory
storage device is not signalled to unload a word into the buffer
register 29. Likewise, no signal follows to the data word available
output conductor 32, and the buffer register 29 is not signalled to
transfer a word to the shift register 31. On the other hand, the
inverter 97 now generates an output signal so this second clock
pulse passes through the AND gate 99 to its output conductor 35 and
on to the shift register 31. This causes the shift register 31 to
shift out the first bit of the 13-bit word in digital fashion to
its output conductor 34. Of course, since no signal has been
supplied to the unload input conductor 27, no change occurs in the
memory storage 21, and no signal is transmitted to the end of cycle
indexing conductor 26. Hence, the address register counter 22 does
not now change.
The same operation as just described for the second clock pulse
takes place for each following clock pulse from the third through
the 13th pulse. For each of these clock pulses, no signal is
supplied to the unload input conductor 27 or to the transfer input
conductor 33 and no signal is transmitted to the word counter 106.
These successive third through 13th clock pulses are transmitted in
order to the shift register 31 to cause the shift register to shift
out the first 12 bits of the 13-bit word it has been holding.
Now, on the 14th pulse passed by the AND gate 86, everything just
described occurs again, with the shift register 31 shifting out the
13th (last) bit of its word. Until this time, the conductor 105 has
carried no signal but, on the 14th pulse, a pulse is transmitted
through the conductor 105 as an indexing signal to the word counter
106, since a complete word has now been shifted out of the shift
register 31. Hence, the word counter 106 registers a 1 for
completion of the first word.
This 1 word count produces no change in the absence of a signal in
the output conductor 107. However, subsequently upon counting five
words, a 5 count output from the word counter 106 is transmitted
through its output conductor 107 to the inverting device 108. As a
result, the inverting device is flipped to interrupt the signal it
has been transmitting. When the signal from the inverting device
108 is interrupted, the AND gate 110 is disabled and no signal
passes through it for the duration lasting from the end of the
fifth word count to the end of the sixth word count. Therefore, the
memory storage device 21 unloads a total of six words in each 0-13
count/cycle of the counter 58, the first occurring on the
introduction of the horizontal sync pulse to the OR gate 113 and
the second through sixth occurring on the introduction of the 1
through 5 counts by the word counter 106.
Likewise, the 1 word count output signal does not change the
absence of a signal in the output conductor 120 since the conductor
120 is connected to receive a signal only when the word counter 106
registers a count of 6. Because of the inverting device 121, the
lack of a signal in the conductor 120 has caused a signal to be
present in the conductor 89 leading to the AND gate 86. However,
when the word counter 106 registers a count of 6, a signal is
transmitted through the conductor 120 to the inverting device 121.
With the presence of a signal in the conductor input 120, no signal
is transmitted through the conductor 89, and the AND gate 86 is
disabled for the duration lasting from the end of the sixth word
count to the following horizontal sync pulse. Hence, no transfers
of words from the memory storage device 21 or the buffer register
29 take place after the end of the sixth word until the next
horizontal sync pulse occurs in the 0-113 count cycle of the
counter 58.
When the address register counter 22 reaches a count that is any
multiple of 256, it generates a 1 signal to its output conductor
36. This 1 signal tags the word that begins a series of 256 words
that constitute a block. This tag signal is transferred through the
conductor 37 from the buffer register 29 along with the 12-bit
memory word to the shift register, and is serially shifted out of
the shift register immediately preceding that 12-bit word.
The signals in the conductor 34 as shifted out of the shift
register 31 constitute a stream of information that begins with a
blank period lasting from the beginning to the end of the blanking
signal followed by six groups of 14 signals. In each group of 14
signals, the first signal is a 1 or a 0 signifying the presence of
absence of a tag signal. The next 12 signals correspond to the data
bits originally derived from the memory device 21. The last signal
is a 0 or gap signal signifying the end of the word. The end of the
sixth word is followed by a 0 signal period that lasts until the
beginning of the next blanking signal.
These signals are converted to analog signals in the digital to
analog converter 128, and the analog signals flow on to the summing
amplifier 130. The other input to the summing amplifier constitutes
a conventional color television black burst signal generated by the
black burst generator 43. In the summing amplifier 130, the black
burst signal is added to the analog signals at each blank period
already mentioned as lasting from the beginning to the end of the
blanking signal.
From the summing amplifier 130, the video signal is modulated by
the RF modulator 132, is amplified and linearly combined with
similar signals from other transmitters in the summing circuits and
amplifier 134, and is transmitted on to the cable network.
In the operation of the receiver 150, the channel selecting means
167 are set to enable the color television receiver front end 151
to receive information from a selected one of several transmission
channels. The selection having been made, the color TV receiver
front end 151 receives a continuous stream of transmitted
information.
The processor 153 delivers an initial instruction signal through
the array of conductors 164-166 to the address register counter 161
instructing the address register counter 161 to supply an initial
address signal through the conductor bank 162 to the memory section
154. This initial address signal identifies a particular location
in the memory section 154 for storage of the first word which the
memory section will receive.
The processor 153 is also programmed to deliver a block selecting
number through the 12 conductors 230 to the comparator 229,
specifying to the comparator 229 which block is desired. This block
specifying number will establish the identity of the 256 word block
that the processor has been programmed to select from the
continuous stream of information being received by the color TV
receiver front end 151.
Finally, the processor 153 is programmed to transmit a start
selection/transfer process signal through the conductor 242 to the
start/stop synchronizer 216. This signal in the conductor 242
enables the start/stop synchronizer 216 to be flipped to its "set"
or "on" condition when an appropriate signal is present in the
conductor 215 leading to the start/stop synchronizer 216. The start
selection/transfer process signal programmed by the processor 153
is also transmitted by the conductor 243 to the block transfer
counter 244 to set the block transfer counter 244 to a count of
0.
Turning now to the stream of information coming from the color TV
receiver front end 151, the video signal emerging from the analog
to digital converter 175 constitutes the digital bit data that is
transmitted serially through the conductor 176 to the assembly
shift register 177. At the same time, the clock pulse signal is
being delivered through the conductor 182 to the AND gate 183 and
simultaneously through the conductor 184 to the AND gate 185. This
clock pulse signal is at half the frequency of the local oscillator
signal emerging from the color TV receiver front end 151 through
the conductor 169. That local oscillator signal produced by the
local oscillator in the television receiver front end is
synchronized and phase-locked to the color subcarrier in the black
burst signal received from the transmission line by the television
receiver front end 151. Hence, the clock pulse signal is in phase
with the basic timing of the transmitted signal from the central
storage transmission system 20.
The clock pulse signal passes through the AND gate 185 except when
the AND gate 185 is blocked during the period from the end of the
sixth word count produced by the word counter 197 through the
period of the blanking signal delivered to the AND gate 185 through
the conductor 192. At all other times, the clock pulse signal
passes through the delay device 206 and is delivered as indexing
pulses to the shift and transfer counter 199.
It will be noted that, initially, the shift and transfer counter
199 has been set to a count of 0 by the horizontal sync pulse
transmitted to it through the conductor 198. This same horizontal
sync pulse also has initially set the word counter 197 to a count
of 0 through transmission of the horizontal sync pulse through the
conductor 196.
The primary function of the shift and transfer counter 199 is to
establish the fact of a full word count. In other words, during
counts of 0 through 12 by the shift and transfer counter 199, no
signal is present in the output conductor 209 and therefore a
signal is present in the output conductor 211 from the inverting
device 210 to keep the AND gate 183 open. Accordingly, the first 13
clock pulses are passed through the AND gate 183 and through the
conductor 212 to signal the assembly shift register to shift
13-data bits from the conductor 176 into the assembly shift
register 177 where these 13 bits are held in a parallel array.
These 13 bits constitute the tag bit plus the 12 bits of the word.
The tag bit will be a 1 for the first word of a 256 word block and
a 0 for all subsequent words in the block.
The 13-shift pulses which are transmitted to the assembly shift
register 177 through the conductor 212 are derived from clock
pulses supplied to the AND gate 183 from the conductor 182.
However, it is the gating of the AND gate 183 by signals in the
conductor 211 that determines the transmission of the 13 shift
pulses. The shift and transfer counter 199 causes gating of the AND
gate 183. This is because the conductor 209 leading from the shift
and transfer counter 199 carries a signal only when the shift and
transfer counter 199 registers 13. Hence, no signal is present in
the conductor 209 when the shift and transfer counter 199 registers
a 0 through 12. When there is no signal in the conductor 209, the
inverting device 210 does produce a signal in its output conductor
211 to hold the gate 183 open and admit 13-shift pulses to the
assembly shift register 177. In this manner, 13 bits of data being
supplied from the conductor 176 are serially shifted into the
assembly shift register 177, the first bit constituting the tag
bit. When the shift and transfer counter 199 registers 13, a signal
is produced in the output conductor 209 and, therefore, no signal
in the conductor 211, closing the AND gate 183. At this time the
full 12 bits of a word plus the 13th tag number bit have been
shifted into and are assembled in the assembly shift register
177.
When the 14th clock pulse occurs, the shift and transfer counter
counts from 13 to 0. During this 14th pulse, a signal is produced
in the conductor 214 to index the word counter 197, because this
signal occurs after a complete word has been counted. Since the
word counter 197 was initially set to 0 by the horizontal sync
pulse in its input conductor 196, this first signal in the
conductor 214 indexes the word counter 197 to a count of 1. The
14th pulse also causes a signal to be transmitted through the
conductor 215 to the start/stop synchronizer 216. This flips the
start/stop synchronizer to its "set" or "on" condition and it
transmits a signal to the AND gate 220 through the conductor
221.
The 14th pulse is also delivered through the conductor 217 and
through the delay device 218 to the AND gate 220. Since there are
signals in both the conductors 219 and 221, the AND gate 220
transmits a signal through the conductors 223 and 225 to both the
AND gates 224 and 226.
It will be recalled that, at this time, the block transfer counter
244 has been set to 0 by the signal in the conductor 243.
Therefore, an output signal appears in the conductor 248, but
because of the inverting device 249, no signal appears in the
conductor 250. Hence, the gate 226 is closed and cannot pass the
signal from the conductor 225. Whether or not the gate 224 is open
depends upon the condition of signals supplied to the comparator
229. The comparator 229 delivers a signal to its output conductor
228 only when there is a match of the 13 signals constituting the
12-bit block specifying number supplied through the conductors 230
and the fixed 1 tag bit number in the conductor 232 with the 13
signals transmitted through the conductors 234 and 235 from the
assembly shift register. If there is a match, the word assembled in
the assembly shift register must contain a 1 in the tag bit
position, indicating that the word is the initail word of a block.
Furthermore, the signals in the 12 conductors 234 and the 12
conductors 230 to the comparator must also match, indicating that
the block identifying number is the specific one sought by the
process or 153. When there is such a match, a signal is transmitted
from the comparator 229 through the conductor 228 to open the gate
224 because it is now desired to accept this word and the 255 words
which follow it into the memory section 154.
Upon opening the gate 224, the signal from the conductor 223 is
transmitted through the conductor 252 to the OR gate 253. This
pulse is delivered from the OR gate 253 to the transfer input
conductor 255 leading to the buffer register. Upon receipt of this
pulse, the buffer register causes the 12-bit signals of the word
then present in the assembly shift register 177 to be transferred
in parallel to the buffer register 238.
The output signal from the OR gate 253 is also delivered by the
conductor 256 to the memory section 154. After the internal delay
in the memory section 154, the 12-bit word then stored in the
buffer register 238 is transferred in parallel to the specific
location within the memory section 154 dictated by the address
register counter output conductor 162. After the 12-bit word has
been stored in the memory section 154, an end-of-cycle pulse is
transmitted through the conductor 163 from the memory section to
the address register counter 161 to index the address register
counter 161 to its next word address. The address register counter
161 then sends this new address signal through the conductor bank
162 to direct the memory section 154 regarding the positioning of
the next word it will receive from the buffer register 238.
The signal from the OR gate 253 is also delivered through the
conductor 257 and the delay device 258 back to the block transfer
counter 244 to index the block transfer counter to its next or 1
count. With the presence of a 1 count in the block transfer counter
244, no signal is transmitted to the output conductor 248 and
therefore a signal is supplied from the inverting device 248
through the conductor 250 to open the AND gate 226. Similarly, on
succeeding counts of the block transfer counter from 2 through 255,
the AND gate 226 will be opened. Therefore, although the AND gate
224 is opened only for the initial appropriate block identifying
number, the AND gate 226 passes pulses for the succeeding 255 words
to the OR gate 253. On the 256th count by the block transfer
counter 244, the block transfer counter 244 will transmit a signal
through the conductor 245 to stop the start/stop synchronizer 216
and through the conductor 246 to advise the processor 153 that it
has then received the entire 256 words of the block it had been
programmed to receive.
In this process, each time the shift and transfer counter 199 has
completed the count of 13 and has assembled a word in the assembly
shift register 177, it goes back to a count of 0. The word
assembled in the assembly shift register will then be transferred
to the buffer register and subsequently to the memory section 154
as already described. The 0 count in the shift and transfer counter
199 will again open the AND gate 183 to cause 13 additional clock
pulses to be transmitted to the assembly shift register, causing
the parallel assembly of 13 additional digits of data in the
assembly register 177. For every group of 13 pulses, another
indexing signal is transmitted to the word counter 197. On each
count of six words, the word counter 197 delivers a signal to the
conductor 200 through the inverting device 201, resulting in no
signal being present in the conductor 202. This blocks the AND gate
185. Subsequently, a blanking signal from the signal standardizer
188 passes through the inverting device 190 resulting in no signal
present in the conductor 192. This lack of a signal in the
conductor 192, due to the transmission of a blanking signal, holds
the gate 185 open until the end of that blanking signal or until
the next information carrying video signal.
Thus, this information transmission and multiple receiver system
continuously transmits or broadcasts, computer programs from a
large central memory (or several large central memory sources) to a
large number of receivers that have data processors. The data
processors, which may be of low compute power and therefore
relatively inexpensive, are empowered with the logic of the
computer programs being continuously broadcast. Each receiver can
select programs from the continuous broadcast stream for
application and its data processor. As a result, the compute power
of each receiver is greatly compounded.
* * * * *